[Assassination] Deadly Poison (DoT) low ticks

Hi.
I just started practicing PvE a few days ago after I hit 90. (Leveled by only doing PvP as Subtlety)

My question is about the Deadly Poison DoT ticks.

When I look at my recount data it says,

"Deadly Poison 637 18.5%" for Deadly Poison.

But for the dot ticks it says,

"Deadly Poison (DoT) 206 11.7%" and is 5th for my damage done spells.

Is this normal?
I saw another rogues Deadly Poison (DoT) damage being top for his damage done spells. (on the same fight, which was the last boss of HoF LFR 2nd half)

Afaik, haste doesn't seem to effect the ticks of Deadly Poison (DoT), so I don't have a clue what I'm doing wrong.
And the counts between the Deadly Poison and Deadly Poison DoT is too far apart, 637 & 206.

one of the things to keep in mind is if you are hit capped and whether or now you are comfortable with the amount of expertise you have. if you are fine with those two factors and other players have not complained about you then you should feel comfortable, depending on your dps of course but that comes with gear and timing more or less